Modes of Operation

RESET:

In the RESET mode all the internal registers are reset to the default values. Reset is entered always if input

NRST is LOW or internal Power On Reset is active. Power On Reset (POR) will activate during the chip

startup or when the supply voltages V

POR will inactivate and the chip will continue to the STANDBY mode. NSTBY control bit is low after POR

by default.

STANDBY:

The STANDBY mode is entered if the register bit NSTBY is LOW and Reset is not active. This is the low

power consumption mode, when all circuit functions are disabled. Registers can be written in this mode and

the control bits are effective immediately after start up.

STARTUP:

When NSTBY bit is written high, the INTERNAL STARTUP SEQUENCE powers up all the needed internal

blocks (V

by the internal state-machine. If the chip temperature rises too high, the Thermal Shutdown (THSD)

disables the chip operation and STARTUP mode is entered until no thermal shutdown event is present.

BOOST STARTUP: Soft start for boost output is generated in the BOOST STARTUP mode. The boost output is raised in low

current PWM mode during the 20ms delay generated by the state-machine. All LED outputs are off during

the 20ms delay to ensure smooth startup. The Boost startup is entered from Internal Startup Sequence if

EN_BOOST is HIGH or from Normal mode when EN_BOOST is written HIGH.

NORMAL:

During NORMAL mode the user controls the chip using the Control Registers. The registers can be written

in any sequence and any number of bits can be altered in a register in one write.

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